Library of rocks a hidden gem in the Midlands

Like the library in most any community, the one off Broad River Road has plenty of information in the rows of shelves lining the building’s interior.

But there are no books.

This library is filled with rocks, dirt and minerals. Slices of the earth’s crust, unearthed by geologists through the years, are kept in the 160-foot-long metal warehouse behind a small government office in northwest Columbia.

Known as cores, these tubular slivers provide insight into South Carolina’s varied and sometimes complex geology. Core samples kept at the warehouse indicate how much rock, sand, limestone or other materials can be found below the surface in certain areas of the state – and that’s often important to businesses.

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Gold exploration companies use samples from the core repository to help determine where to look for large deposits. Farmers rely on core sample studies to locate groundwater they need for irrigating crops. Big companies use core data to find water they want to use in industrial processes.

“It’s a phenomenal resource to have for the state,” said Bruce Campbell, a groundwater specialist with the U.S. Geological Survey in Columbia. “Hopefully, it’ll be there for a long time.”

The repository, operated by the S.C. Department of Natural Resources, contains more than 1,600 core samples stacked floor to ceiling on 307 shelves. The samples are kept in 14,000 cardboard boxes and collectively weigh nearly 400 tons.

Cores, which resemble skinny stone columns, typically are about 3 feet long and about 1 to 2 inches around. They have been donated through the years by industries or scientific research teams from drilling work they’ve done.

As opposed to a book library, the core library presents unique challenges for those wanting information. Cores are so heavy it sometimes takes several people to grab them from a shelf. The average box in the repository weighs 40 to 60 pounds.

“Some of these rock cores are outrageous,” chief DNR geologist Scott Howard said of their weight. “It takes a crew to pull that down.”

The weight doesn’t deter geologists, particularly those looking for gold.

As interest in gold mining has resumed in South Carolina, a half-dozen exploration companies have made it a point to visit the core repository off Broad River Road.

Gold exploration companies might see an abundance of quartz or pyrite in certain samples, which then gives them clues on whether gold exists in an area. Gold often is associated with these materials.

Miners working on what would become the largest gold mine ever established in South Carolina, a 2,500-acre operation in Lancaster County, relied on data from the core repository, Howard said. He said he recently received an email from an Australian minerals company.

“Most of the time they are looking for a specific area,” Howard said of gold exploration companies. “They’ll come in and set up camp for a week and just go through boxes and boxes of cores. Sometimes they even want a sample.”

Geologists sometimes use the core repository before drilling their own holes to determine whether gold exists. That saves money on drilling expenses, Howard said.

The U.S. Geological Survey also has relied on data from core samples to help determine where underground water is abundant and where it is scarce. Cores can provide detail about the different aquifers that underlie an area. An abundance of course sand, for instance, sometimes indicates that water will move quickly below ground, which can show plentiful supplies.

Campbell recently completed a study of groundwater in Chesterfield County and is currently working on a groundwater availability study for Aiken County.

The latter report is being conducted as concerns rise about the lack of water for irrigation in central South Carolina, west of Columbia. Many people have expressed concern that lower groundwater levels could mean lower river levels in the Edisto River basin, which receives some of its flow from groundwater. Steady groundwater supplies also are vital because most of Aiken County gets drinking water from the ground.

The USGS studies have relied on data DNR groundwater experts had put together after reviewing samples at the core repository, Campbell said.

Core repositories can be found in other places around the country, including North Carolina. The federal government also has a repository in Colorado.

South Carolina’s repository, which is mandated by state law, doesn’t have a specific budget, but is overseen as part of the S.C. Geological Survey’s $15,000 operating budget. The Geogical Survey is a division of the state Department of Natural Resources.